1. Technical Field
The disclosure is related to a light emitting diode (LED) epitaxial structure and a manufacturing method of the same, and particularly to an LED epitaxial structure having good light emitting efficiency and the manufacturing method of the same.
2. Description of Related Art
Light emitting diodes (LEDs) are technologically and economically advantageous solid state light sources. LEDs are capable of reliably providing light with high brightness, hence in the past decades they have come to play a critical role in numerous applications, including flat-panel displays, traffic lights, and optical communications. The conventional procedures for producing LEDs are primarily to epitaxy a layered light emitting structure with pn junction on a sapphire substrate. The performance of such LEDs is seriously degraded by the presence of threading dislocations, which thread vertically through the epitaxial layers. In particular, when a sapphire substrate is used, it does not dissipate heat efficiently and there is a strong tendency of light emission efficiency not to increase linearly in proportion to an input, but to be saturated halfway. It is known in the art that the light emission from electroluminescent devices or from LEDs is limited by the total internal reflection occurring at the surface between the semiconductor substrate wherein the device is fabricated and the surrounding medium. Therefore, what is needed is an LED structure that reduces the amount of emitted light that is lost through various loss mechanisms, thereby increasing the overall output of the device.